Automatic focusing solar printer.



No. 730,583. Patented June 9, 1903.

UNITED STATES PATENT OEEICE.

HERMAN STENDER, OF LOS ANGELES, CALIFORNIA, ASSIGNOR, BY DIRECT ANDMESNE ASSIGNMENTS, TO AUTOMATIC FOCUSING CAMERA COM- PAI Y, ACORPORATION OF ARIZONA TERRITORY.

AUTOMATIC FOCUSING SOLAR PRINTER.

SPECIFICATION forming perror Letters Patent 10.730,583, dated Tune 9,1903- Application filed October 3,1900. Renewed October 13, 1902. SerialNo. 127,184. (No model.)

To @ZZ when?, it may concern: sensitized surface, and the lens changepro- Be it known that I, HERMAN STENDER, a portionately with each otherto properly fo- 5o subject of the German Emperor, residing at cus forthe different degrees of enlargement. Los Angeles, in the county of LosAngeles My invention consists in furnishing the so- 5 and State ofCalifornia, have invented anew lar printer with means for automaticallyand useful Automatic Focusing Solar Printer,j maintaining theappropriate relative disof which the following is a specification.tances between the negative, the sensitized 55 The object ofmylinvention is to produce surface, and the lensv as the same areadmeans whereby photographs can be printed justed for producing printsof greater or less I in any desired enlarged size from a small negasize.

tive by the direct rays of the sun without the My solar printercomprises a box furnished exercise of any technical skill or knowledgewith a partition, a lens in the partition, a 6o upon the part of theprinter. negative-holder at one side of the lens, a By my invention Ipropose to enable amaprint-holder at the other side of the lens, and Iteur photographers with negatives made by differential means forsimultaneously varykodaks or any other cameras to produce clear ing therelative distances between negativebrilliant prints of any required sizefrom a holder, print-holder, and lens. The dier- 65 small negative.ential means may be of any suitable charac- An important object which Ipropose to attergand they may be applied to move any 2O tain by thisinvention is to dispense with the two of the three-named parts to bringthem necessity of expensive lenses and mechanto the distances apart atwhich they are to isms for the production of large photobe adjusted. 7ographic prints. In the form shown in the drawings a differ- Anotherobject is to enable the photograential screw is employed to move theprintpher to produce better perspective effects holder and thenegative-holder. The screwthan have heretofore been possible in thephothread which moves the print-holder is coarser tographic art. Ipropose in practice to conthan the screw-thread which moves the nega- 75 centrate the image from nature through as tive-holder, and both ofsaid threads diminperfect a lens as possible to produce a small ish inpitch proportionately with each other negative and then to enlarge thesmall negatoward the lens, so that each of the holders tive thusproduced by projecting the light diminishes in speed as it approachesthe lens therefrom through a perfect lens with a perand increases inspeed as it moves from the 8o fect focus onto any suitable sensitizedsurlens. It is necessary that the space between face to produce thedesired print. By this vthe lens and .print-holder shall increase and 35 means the correct perspective and atmosdecreasemore rapidly than thespace between pheric effects which appear in nature and the lens and thenegative-holder, and in the which it has heretofore been foundimpossiform shown the speed of one holder will de- 85 ble to produce byprinting directly from a crease when the speed of the otherincreases,negative froma large camera will be brought and vice versa, in a commonratio.

out by the enlargement from the perfect The accompanying drawingsillustrate my small negative. Y invention in its preferred form.

An object of my invention is to make the Figure I is a verticallongitudinal section 9o enlarged print upon contact-printing paper, ofthe solar printer. Fig. Il is a side elevathereby producing an enlargedprint having tion of the solar printer. Fig. III is a front theappearance of being made by direct conelevation, the door and groundglass being tact with the negative. l removed. Fig. IV is `a rearelevation, the

My invention depends upon the principle rear closure being omitted toreceive the that the distances between the negative, the print-form.Fig. V is an enlarged detail of the dierential screw. Fig. VI is adetail of one of the single-thread nuts for the differential screw.

a indicates a solarprinter box, which is impervious to light and foreconomy of space is smaller at one end than at the other.

b is a lens-partition in the box.

c indicates Va lens in the partition.

d indicatesY a print-holder, and e the form upon which the sensitizedmaterialf to form the print will be placed. The lens c is stationed tobe on a line with the center of the Ysensitized materialfwhen the sameisin position.

. g indicates-the negative-holder at the opposite side ofgthe partitionand lens from the print-holder.

7L indicates a negative in the negativeholder.

i indicates ground glass at the negative end of the box.

j indicates a door to exclude light from the ground glass and to beopened to expose the negative to the light. Y

7c indicates a door or cap at the rear end to allow the print-holdingform e with the print j thereon to placed on the print-holder.

Z indicates a side door opening into the box between the print and thelens to allow inspection of the print in case printing-outpaper isemployed. When the closures j, 7c, and Z are closed, the box isimpervious to light.

m indicatesa differential screw furnished with a coarsethread '1L at oneend and a fine thread Yo at the other end. Each of these threadsproportionately diminishes in pitch.

' lens the thread for moving the print-holder will be, say, about twelveinches long, and its coarser end will be about four pitch at abouttwenty-one inches from the lens and will diminish to about eight pitchat the other end of said thread. This is indicated by the characters 4and 8 in Fig. V. The thread. for moving the negative-holder will then beabout three inches long and the pitch will increase from thirty-two tosixteen pitch in that length, as indicated by the characters 32 and 16in Fig. V. The focus distances vary uniformly for any lens, but varydifferently with different lenses. Consequently the differential screwsare not always alike for a given size of lens.

The rule for determining the pitch of the threads relative to the lensand the work to be performed by the printer is as follows: Thenegative-holder will first be stationed at the position for the largestpicture to be taken,

and the print-holder will be stationed at its station for the largestpicture, and when a perfect focus is produced from the negative throughthe lens onto the print-form e these points are marked, the one beingthe inner end of the negative-holder-moving thread-'and the-other beingthe outer end of the printholder-moving thread. Then the print-form eand negative-holder are set in focus for the smallest size of printdesired, and this point will be marked as determining the inner end ofthe print-holder-moving thread and the outer end of thenegative-holder-moving thread. Then one threadis cut to convenience,diminishing regularly in pitch from end-.to end toward the lens. Theother thread is then cutfrom end to end. the same number.of turns, thepitch diminishing toward thelens in proportion with the first thread.Then the holder-moving nuts p being fastened to their respectiveholders, will be applied to their respective threads, the printholdernut being at the outer end ofthe print-holder-moving thread when thenegativer-holder nut is at the inner end of the negative-moving thread.Then when lthe differential screw m is turned the negativeholder will bemoved away from the lens with an increasing speed and the print-holderwill be moved toward the lens at a speed decreasingrproportionately withthe speed of the negative-holder, and the fecus will be maintainedthroughout the entire movement of the negative-holderand the lens-holderfrom end to end of their respective threads, so that no skill and noinspection whatever is; required for producing the exact focus.

In practice to produce a large print from a small negative the negativewill be put in position and the differential screw wilt be turned tobring lthe holders to the points to produce the enlargement desired.Thenthe printer will be taken into a dark room, the sensitized materialwill be placed upon the form e therefor, and said form will be fastenedin position in the holder d. VYThen the closures 7a and j will beclosed, and the printer will be taken to the light and directed towardthe sun or other requisite light source, and the exposure is then madeby opening the door j for the determined length of time. The printerwill then be taken to the dark room, and the print lcan then be handledand developed in the manner customary for the treatment of sensitizedpaper.

Any character of sensitized paper or other sensitized material may beused, and the results obtained, in so far as the printing is considered,will be substantially the same as with contact-printing with the samepaper or material.

What I claim, and desire to secure by Letters Patent of the UnitedStates, is-

1. A solar printer comprising a box furnished with a partition; a lensin the partition; a negative-holder at one side of the lens aprint-holder at the other side of the IOO IIO

lens; and a differential screw for simultaneously varying the distancesbetween negativeholder, print-holder and lens.

2. A solar printer comprising a box furnislied with a partition; ,a lensin the partition; a negative-holder at one side of the lens; aprint-holder at the other side of the lens; and a dierential screw forsimultaneously operating the negative-holder and printholder for varyingthe distances between negative-holder, print-holder and lens.

3. A solar printer comprising a box furnished with a partition; a lensin the partition; a negative-holder at one side of the lens; aprint-holder at the other side of the lens; and a differential screwfurnished with a coarse thread diminishing in pitch toward the lens formoving the print-holder toward and from the lens, and also furnishedwith a fine thread diminishing toward the lens for moving thenegative-holder toward and from the lens.

4. The combination with a solar-printer lens, negative-holder andprint-holder, of a differential screw for moving the negativeholder andprint-holder, the pitch of the threads respectively diminishing towardthe lens, and 'the negative-holder thread being of less pitch than andproportionate with the pitch of the print-holder-moving thread.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, at Los Angeles, lalifornia, this24th day of September, 1900.

HERMAN STENDER.

Witnesses:

J AMES R. ToWNsEND, JULIA ToWNsEND.

